This invention relates to a transistor structure and more specifically relates to a novel transistor chip arrangement which permits the manufacture of a single high current, high power transistor structure.
Thyristors are commonly used in high power switching applications such as those requiring currents of 100 amperes or more at voltages of 100 volts and above. These devices are provided in single packages such as the conventional stud mounted TO-83 package which can be easily mounted for any given switching application. The use of a transistor as a power switching device has several advantages over the thyristor since the transistor does not need a commutation circuit for turn-off. This makes the overall arrangement more compact and simpler in design. Moreover, the transistor can operate at frequencies of 5-10 kilohertz as compared to only 2-3 kilohertz for thyristors. The power capability of individual transistors, however, has been relatively low so that numerous transistors had to be connected in parallel to obtain the necessary current rating for a high power operation. A single high current, high power transistor such as one having a continuous collector current of 100 amperes or more is very desirable, but single devices capable of this rating and which can be manufactured with conventional equipment at high speed and reliability are not available.